Various embodiments of a motor/pump unit are described herein. In particular, the embodiments described herein relate to an improved motor/pump unit for a power-steering arrangement in a motor vehicle.
A motor/pump unit comprising a housing, a hydraulic pump unit with a pump module, and a motor unit with a drive motor is shown in DE 203 02 534 U1, and corresponding US 2006/039804 which published on Feb. 23, 2006. In a motor/pump unit of this type, the outer surfaces, in particular of the outer housing surrounding the motor and pump units, emit sound outwards. Furthermore, in conventional motor/pump units without special sound-absorbing and sound-damping measures, the structure-borne sound generated by the motor and pump units is passed on through the connected components into the passenger compartment and is emitted there as sound transmitted by air. The connected components may also be stimulated to natural vibrations which again leads to the emission of air-borne sound.
In DE 203 15 224 U1, and corresponding US 2005/0053487 which published on Mar. 10, 2005, to reduce the noise development in a hydraulic system with a motor/pump unit, it is proposed to couple at least a portion of the motor/pump unit to the outer housing via a damping bearing which can be realized only at a relatively high cost.